And here is a tiny tropical water lily I just moved out. It will fill the surface with leaves about the size of the palm of your hand and be flowering in just a few weeks. This variety, Dauben, stays small and is vivaporous, so it can grow new plants from the leaves. Since it is tropical and would die during winter, I just take a few leaves to start new plants and nurse the plantlets along in a small plastic container over the winter. Once I move them into gallon size pots from the tiny pots I keep them in over the winter, they take off quickly. The nice thing with the tropical ones is they hold the flowers up over the water so they’re easier to se in containers, plus they don’t try to go dormant, so will be flowering right up until a hard frost/freeze finally takes them out.
Mamuang, I’ve participated in a number of forums and sites before, including the old garden web and probably to a larger extent https://www.gardenpondforum.com/ which is a nice community. It is interesting that you don’t see as many people doing things with container water gardens and instead focusing more on ponds. Most of the info on ponds has some relevance, but with containers you don’t usually worry about any type of filtration, etc.
The truth is most pond plants are fast growers and pretty easy. The biggest challenge is finding plants that are the right scale for smaller containers. Most of mine are 20-26 inches in diameter and at least 15 inches deep, so a full sized water lily would quickly outgrow it as would full sized lotus. Most of the smaller types you have to track down at special nurseries since you won’t find them at your local garden centers.
Besides water lily and lotus plants, there are a lot of other easy to keep plants you can try. I like Pickerel rush, which is a native with attractive blue flower spikes that the pollinators love, especially bumbles. It multiplies quickly and flowers on new growth so you can have season long flowering once it gets going. There also many types of Iris, etc., although they aren’t as long flowering. The pickerel rush and Iris are bog type plants which you can have barely covered with water or even with the water below the surface as long as their roots stay very moist.
By the way, with lotus and lilies, I always throw in a few guppies or fish called rosy red minnows (a color variant of native fat head minnows) and they eat any mosquito larva.
Here is an Iris called Claude Redmond in a bog area (just pea gravel) with some dwarf cattails in back and pennywort growing on the surface. Excuse all the weeds in the back…